Olivier Giroud offered his tribute to the Hillsborough victims on the 25th anniversary of the disaster after his stunning goal helped Arsenal to a 3-1 home win over West Ham United.

The France striker, who has struggled for form in recent weeks, showed a wonderful touch to bring down a high ball before finishing to put his team 2-1 in front and reignite their hopes of Champions League qualification.

The supporters at the Emirates Stadium had observed a period of silence before the game in memory of the 96 supporters who lost their lives at Hillsborough and Giroud marked his goal by removing the black armband, kissing it and lifting it towards the sky.

"I didn't know exactly the story [of Hillsborough] but I was really sensitive to it and I just wanted to pay homage to them," Giroud said. "I dedicate my goal to them. It was normal for me to think of the families."

Giroud had struggled in the first-half, missing one gilt-edged chance, but his 20th goal of the season in all competitions revived his confidence. It was a beauty that reminded many observers of some of Dennis Bergkamp's very best finishes.

"It was a perfect first touch," Arsène Wenger, the Arsenal manager, said. "You need that if you want to score the goal. What I liked is that he used his upper body first to make some space and despite that he managed to have a great first touch. And after he finished well.

"Olivier is a great guy, with a great mentality. He has gone through a difficult period, as you know, and I think it affected his game for a while, and his confidence. At half-time he was very, very down because he missed a great chance but he responded very well in the second-half because mentally he is a very strong guy."

The controversy of the evening came in the 18th minute when the West Ham winger Matt Jarvis nicked the ball ahead of Bacary Sagna inside the area and felt the Arsenal full-back swipe at him.

But Jarvis did not go down and the referee, Kevin Friend, did not whistle for the penalty. Sam Allardyce, the West Ham manager, was unimpressed, even though he blamed his team's defensive lapses for the defeat. "The fact is that when you stay on your feet refs don't give penalties," Allardyce said. "For six to eight years now and three different managers of the PGMOL – Don, Hackett, Riley – it's all the same. The ref finds it very difficult to give. For honesty, there is no reward. So what do I do?

"A foul is a foul. It doesn't matter whether you go down or stay on your feet. You get slaughtered for diving but when someone is honest you don't get what you should get. It's a critical decision so you have to make the ref's mind up. If there is contact you should go down and make the referee's mind up for him. There is no reward for being honest."

Wenger said that he was "grateful" to Jarvis. "I don't think it was a penalty but he touched him, yes," Wenger said. "Can you be too honest? I leave you that judgment. You want people to be honest if you thought it was a penalty. Maybe if he made a theatrical dive he would have got it."

Arsenal's manager, undermined by injuries and the after-effects of Saturday's gruelling FA Cup semi-final penalty shootout win over Wigan Athletic, opted to rest Aaron Ramsey and Alex Oxlade-Chamberlain, although the former did come on as a 72nd-minute substitute. The starting XI was the oldest, on average, that he had selected in the Premier League since May 2003 against Leeds United. Giroud was the youngest outfield player at 27.

"It was a gamble," Wenger said. "But I trusted the experience of the players. It was an unusual around-30 team and that experience, of course, helps when you are a little bit back against the wall.

"The wins over Wigan and now West Ham improve the confidence of the team. We have one advantage [in the race for Champions League qualification] – the picture is very clear. We have to win our remaining games. It doesn't depend solely on us but there's a good chance that if we win all of our remaining games we will qualify."

Mesut Özil should return for Sunday's visit to Hull City. The midfielder has been out since 11 March, when he tore a hamstring in the Champions League tie at Bayern Munich.

• This article was amended on 16 April 2014. An earlier version said that Giroud was the oldest, rather than youngest, outfield player at 27.